In Tonyr1084 last schematic when voltage is applied the relay only operates for a second. Does a capacitor stop the flow when fully charged

 

Does a capacitor stop the flow when fully charged

Correct!

 

Does a capacitor stop the flow when fully charged?

Yes. The cap - when at zero volts - will draw current until it reaches about 1/3 the necessary voltage. As the cap charges higher and higher the current flows less and less. The relay will not energize again until the capacitor has sufficiently drained so that the next time when activated it will do so again. The cap will charge through the coil until it reaches nearly full voltage but the relay will have dropped out long time before then (relatively speaking - - - for a cap milliseconds can be a long time).